Saturday, 22 July 2017

#ResearchSpeak: are you a drinker?

What is the evidence that alcohol is good for you? #ResearchSpeak #MSBlog

The following study implies that moderate alcohol consumption is associated with lower disability and suggest red wine is good for you. However, moderate red wine consumption (1-3 glasses per week) was associated with a faster increased in MRI T2 lesion volume, i.e. focal MRI activity. How do we square this circle? We don't the results are not that convincing and suggest an association. In other words alcohol drinking may be associated with other factors that are actually responsible for the lower levels of disability. The association with red wine drinking looks like a false positive and the positive spin in this article could be due a framing effect based on the marketing of red wine as an anti-ageing agent. A framing effect is the interpretation of results in a particular way based on a bias (frame) that has been established by past experiences or prior knowledge.

There has been work done on resveratrol, an anti-oxidant, in red wine as an anti-ageing, and neuroprotective, compound. The problem is that the amount of resveratrol you get from drinking red wine is too low to have much biological impact. Despite this the French wine industry has managed to get the message across that red wine is good for you.

This paper must be balanced against the literature showing how bad excessive alcohol intake is for your health overall. More recently excessive, and even moderate, alcohol consumption has also been shown to reduce cognition.

I must point out that the levels of consumption of alcohol studied in this paper are quite low. This study in not going to alter my practice and I will continue to recommend that if you choose to drink please do so in moderation and if you choose to be teetotal that is also fine. The evidence that alcohol is neuroprotective is very weak. We need well designed and larger studies to control for con-founders before making any unrealistic claims about the benefits of alcohol to pwMS. Diaz-Cruza et al. The effect of alcohol and red wine consumption on clinical and MRI outcomes in multiple sclerosis. Multiple Sclerosis and Related Disorders. Volume 17, October 2017, Pages 47-53.

Background: Alcohol and in particular red wine have both immunomodulatory and neuroprotective properties, and may exert an effect on the disease course of multiple sclerosis (MS).

Objective: To assess the association between alcohol and red wine consumption and MS course.

Methods: MS patients enrolled in the Comprehensive Longitudinal Investigation of Multiple Sclerosis at the Brigham and Women's Hospital (CLIMB) who completed a self-administered questionnaire about their past year drinking habits at a single time point were included in the study. Alcohol and red wine consumption were measured as servings/week. The primary outcome was the Expanded Disability Status Scale (EDSS) at the time of the questionnaire. Secondary clinical outcomes were the Multiple Sclerosis Severity Score (MSSS) and number of relapses in the year before the questionnaire. Secondary MRI outcomes included brain parenchymal fraction and T2 hyperintense lesion volume (T2LV). Appropriate regression models were used to test the association of alcohol and red wine intake on clinical and MRI outcomes. All analyses were controlled for sex, age, body mass index, disease phenotype (relapsing vs. progressive), the proportion of time on disease modifying therapy during the previous year, smoking exposure, and disease duration. In the models for the MRI outcomes, analyses were also adjusted for acquisition protocol.

Results: 923 patients (74% females, mean age 47 ± 11 years, mean disease duration 14 ± 9 years) were included in the analysis. Compared to abstainers, patients drinking more than 4 drinks per week had a higher likelihood of a lower EDSS score (OR, 0.41; p = 0.0001) and lower MSSS (mean difference, − 1.753; p = 0.002) at the time of the questionnaire. Similarly, patients drinking more than 3 glasses of red wine per week had greater odds of a lower EDSS (OR, 0.49; p = 0.0005) and lower MSSS (mean difference, − 0.705; p = 0.0007) compared to nondrinkers. However, a faster increase in T2LV was observed in patients consuming 1–3 glasses of red wine per week compared to nondrinkers.

Conclusions: Higher total alcohol and red wine intake were associated with a lower cross-sectional level of neurologic disability in MS patients but increased T2LV accumulation. Further studies should explore a potential cause-effect neuroprotective relationship, as well as the underlying biological mechanisms.

8 comments:

It's on the fence about resveratrol and MS, I remember reading. Unless the following is not valid anymore:

" People with multiple sclerosis (MS) are being warned against taking resveratrol supplements, after a new study using two MS models has found that the compound worsened MS-like neuropathology and inflammation, and had no neuroprotective effects.

" Resveratrol may have detrimental effects in some disease conditions and should be discouraged for supplemental use by MS patients pending further research."

Results of the study were published in The American Journal of Pathology. 2013.

As a society, we have a big problem with our attitude to alcohol. I'm about to go on holiday with friends and family. Most of them will be drinking alcohol every night and some of them will be getting through most of their week's recommended maximum allowance of alcohol every night. A horrible example for my teenagers and very dull for me.

Gavin, this is great, many thanks for responding when George passed on my question. I'm fortunate to have access to all the literature via work and I do what most physicists do - amatuer attempts at all areas of everything (I'm a prof of climate change impacts).

Diaz-cruz are upfront about the possible confounding factors. http://eu.wiley.com/WileyCDA/PressRelease/pressReleaseId-102899.html also has a disclaimer - but they do at least have a crack at identifying mechanisms.

Is the research being over-sold? (I understand the pressure to publicise..). Salt is another good one, again where mechanisms are cited, e.g. https://mssociety.ca/research-news/article/new-studies-on-the-role-of-salt-in-autoimmunity

Any thoughts on that? Is epidemiology with some supporting mechanisms ever sufficient for public health advice?

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